BANGKOK (AFP) - At least six people were wounded in twin blasts in southern Thailand's main commercial city of Hat Yai - the gateway to the kingdom's insurgency-stricken deep south, authorities said on Tuesday.

The blasts rocked the city in the early afternoon with one detonating near a convenience store and the other exploding by apartments being built for local police.

Television footage showed thick billows of smoke near the apartments as firefighters battled a blaze sparked by the device which was hidden on a parked motorcycle.

"There were two bombs attacks, at least six people were injured - none of them is in a serious condition," Grisda Boonrach, Songkhla provincial governor said.

Local police said the bombs were around 25 minutes apart and confirmed the casualties.

Although authorities were not immediately sure who carried out the blasts, suspicion will inevitably fall on insurgents from Thailand's three Muslim-majority southern provinces which border Malaysia.

Hat Yai, the largest city in Thailand's south which is popular with Malaysian and Singaporean tourists, was targeted in 2012 by a car bomb at a city hotel which sparked a blaze that killed three people, wounded hundreds and left parts of the city centre resembling a war zone.

The city is a one-hour drive to Pattani, one of three provinces which have battered by a decade-long war which has claimed more than 6,000 lives - the majority civilians.

The conflict pits shadowy insurgents in the Muslim Malay area against Thai security forces, but Muslim and Buddhist civilians are most often the victims of the near-daily bombings, shootings and sometimes beheadings.

Thailand annexed the deep south more than a century ago.

The rebels want a level of autonomy, accusing Thai authorities of riding roughshod over their distinct culture and carrying out human rights abuses.

Observers say there has been an uptick in the violence in recent months following the suspension of peace talks between some rebel factions and Thai authorities.

The talks floundered as political turmoil in Bangkok engulfed the government of Yingluck Shinawatra - but all sides have expressed hopes of reviving them over coming months.